M. R. Sheikhmohseni, S. Ansari Lale, S. M. A. Boutorabi,
Volume 12, Issue 1 (5-2026)
Abstract
This study presents a comparative evaluation of SMAW and GMAW welding processes for blade-to-shaft joints in St37 steel industrial mixers operating in lead-processing environments. The effects of welding process selection and joint geometry modification on the microstructural and mechanical properties of the welded joints were investigated. The results showed that the use of the GMAW process reduced the average heat-affected zone (HAZ) width from 1532 μm to 871 μm, corresponding to a 43.1% reduction compared to SMAW. In addition, the ultimate tensile strength increased from 376 MPa for SMAW joints to 400 MPa for GMAW joints, representing a 6.4% improvement. Microhardness measurements revealed an increase in the average HAZ hardness from 145 HV to 160 HV, corresponding to a 10.3% increase. Microstructural examinations also revealed noticeable differences in the characteristics of the weld metal and HAZ produced by the two welding processes. The findings indicate that the combination of GMAW and optimized joint geometry can improve the mechanical performance and reliability of blade-to-shaft joints in industrial mixers.
